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| author |   Theodore Ts'o <tytso@mit.edu> | 2014-03-08 19:51:16 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2014-03-08 19:51:16 -0500 |
| commit | 42cf3452d5f5b0817d27c93e4e7d7eab6e89077d (patch) | |
| tree | 106d8e934c1c930d4fae822c76ff18d493492729 /tools/perf/scripts/python/export-to-postgresql.py | |
| parent | jbd2: don't hold j_state_lock while calling wake_up() (diff) | |
| download | linux-dev-42cf3452d5f5b0817d27c93e4e7d7eab6e89077d.tar.xz linux-dev-42cf3452d5f5b0817d27c93e4e7d7eab6e89077d.zip | |
jbd2: calculate statistics without holding j_state_lock and j_list_lock
The two hottest locks, and thus the biggest scalability bottlenecks,
in the jbd2 layer, are the j_list_lock and j_state_lock. This has
inspired some people to do some truly unnatural things[1].
[1] https://www.usenix.org/system/files/conference/fast14/fast14-paper_kang.pdf
We don't need to be holding both j_state_lock and j_list_lock while
calculating the journal statistics, so move those calculations to the
very end of jbd2_journal_commit_transaction.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'tools/perf/scripts/python/export-to-postgresql.py')
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